Methods for placing a stent in a branched vessel

ABSTRACT

Methods for placing a stent in a branched vessel include stretching the stent, aligning the stent within a target location at a branched vessel and releasing it for expansion at the target location.

CROSS REFERENCES

This application claims the benefit of U.S. Provisional Application No.60/______, filed Jan. 4, 2006; and also claims the benefit of U.S.Provisional Application No. 60/752,128, filed Dec. 19, 2005; and furtheris a continuation-in-part application of U.S. patent application Ser.No. 11/241,242, filed Sep. 30, 2005 which is a continuation-in-part ofU.S. patent application Ser. No. 11/033,479, filed Jan. 10, 2005, whichare incorporated herein by reference in their entirety noting that thecurrent application controls to the extent there is any contradictionwith any earlier applications and to which applications we claimpriority under 35 USC §120.

FIELD OF THE INVENTION

The present invention relates to methods for placing a device in theform of an adjustable stent useful in the treatment of vascular diseasein branched vessels. The methods include stretching the device, aligningwithin a target location at a branched vessel and releasing it forexpansion at the target location.

BACKGROUND OF THE INVENTION

It is well known in the prior art to treat vascular disease withimplantable stents and grafts. For example, it is well known in the artto interpose within a stenotic or occluded portion of an artery a stentcapable of self-expanding or being balloon-expandable. Similarly, it isalso well known in the prior art to use a graft or a stent graft torepair highly damaged or vulnerable portions of a vessel, particularlythe aorta, thereby ensuring blood flow and reducing the risk of ananeurysm or rupture.

A more challenging situation occurs when it is desirable to use a stent,a graft or a stent graft at or around the intersection between a majorartery (e.g., the abdominal aorta) and one or more intersecting arteries(e.g., the renal arteries). Use of single axial stents or grafts mayeffectively seal or block-off the blood flow to collateral organs suchas the kidneys. U.S. Pat. No. 6,030,414 addresses such a situation,disclosing use of a stent graft having lateral openings for alignmentwith collateral blood flow passages extending from the primary vesselinto which the stent graft is positioned. The lateral openings arepre-positioned within the stent based on identification of the relativepositioning of the lateral vessels with which they are to be aligned.U.S. Pat. No. 6,099,548 discloses a multi-branch graft and a system fordeploying it. Implantation of the graft is quite involved, requiring adiscrete, balloon-deployable stent for securing each side branch of thegraft within a designated branch artery. Additionally, a plurality ofstylets is necessary to deliver the graft, occupying space within thevasculature and thereby making the system less adaptable forimplantation into smaller vessels. Further, delivery of the graft andthe stents requires access and exposure to each of the branch vesselsinto which the graft is to be placed by way of a secondary arteriotomy.These techniques, while effective, may be cumbersome and somewhatdifficult to employ and execute, particularly where the implant siteinvolves two or more vessels intersecting the primary vessel, all ofwhich require engrafting.

The use of bifurcated stents for treating abdominal aortic aneurysms(AAA) is well known in the art. These stents have been developedspecifically to address the problems that arise in the treatment ofvascular defects and or disease at or near the site of a bifurcation.The bifurcated stent is typically configured in a “pant” design whichcomprises a tubular body or trunk and two tubular legs. Examples ofbifurcated stents are provided in U.S. Pat. Nos. 5,723,004 and5,755,735. Bifurcated stents may have either unitary or modularconfigurations in which the components of the stent are interconnectedin situ. In particular, one or both of the leg extensions are attachableto a main tubular body. Although the delivery of modular systems is lessdifficult due to the smaller sizes of the components, it is difficult toalign and interconnect the legs with the body lumen with enoughprecision to avoid any leakage. On the other hand, while unitary stentsreduce the probability of leakage, their larger structure is oftendifficult to deliver to a treatment site having a constrained geometry.

While the conventional bifurcated stents have been used somewhatsuccessfully in treating AAAs, they are not adaptable where the implantsite is within the aortic arch. The arch region of the aorta is subjectto very high blood flow and pressures which make it difficult toposition a stent graft without stopping the heart and placing thepatient on cardiopulmonary bypass. Moreover, even if the stent graft isable to be properly placed, it must be secured in a manner to endure theconstant high blood flow, pressures, and shear forces it is subjected toover time in order to prevent it from migrating or leaking.Additionally, the aorta undergoes relatively significant changes (ofabout 7%) in its diameter due to vasodilation and vasorestriction. Assuch, if an aortic arch graft is not able to expand and contract toaccommodate such changes, there may be an insufficient seal between thegraft and the aortic wall, subjecting it to a risk of migration and/orleakage. Further, the complexity (e.g., highly curved) and variabilityof the anatomy of the aortic arch from person to person makes it adifficult location in which to place a stent graft. While the number ofbranch vessels originating from the arch is most commonly three, namely,the left subclavian artery, the left common carotid artery and theinnominate artery, in some patients the number of branch vessels may beone, more commonly two and in some cases four, five or even six.Moreover, the spacing and angular orientation between the tributaryvessels are variable from person to person.

In order to achieve alignment of a side branch stent or a lateralopening of the main stent with a branch vessel, a custom stent designedand manufactured according to each patient's unique geometricalconstraints would be required. The measurements required to create acustom manufactured stent to fit the patient's unique vascular anatomycould be obtained using spiral tomography, computed tomography (CT),fluoroscopy, or other vascular imaging system. However, while suchmeasurements and the associated manufacture of such a custom stent couldbe accomplished, it would be time consuming and expensive. Furthermore,for those patients who require immediate intervention involving the useof a stent, such a customized stent is impractical. In these situationsit would be highly desirable to have a stent which is capable ofadjustability in situ while being placed. It would likewise be highlydesirable to have the degree of adjustability sufficient to allow for adiscrete number of stents to be manufactured in advance and available toaccommodate the required range of sizes and configurations encountered.

Another disadvantage of conventional stents and stent grafts is thelimitations in adjusting the position of or subsequently retrieving thestent or stent-graft once it has been deployed. Often, while the stentis being deployed, the final location of the delivered stent isdetermined not to be optimal for achieving the desired therapeuticeffect. During deployment of self-expanding stents, the mode ofdeployment is either to push the stent out of a delivery catheter, ormore commonly to retract an outer sheath while holding the stent in afixed location relative to the vasculature. In either case the distalend of the stent is not attached to the catheter and, as such, is ableto freely expand to its maximum diameter and seal with the surroundingartery wall. While this self-expanding capability is advantageous indeploying the stent, it presents the user with a disadvantage whendesiring to remove or reposition the stent. Some designs utilize atrigger wire(s) to retain the distal end of the stent selectively untilsuch time as full deployment is desired and accomplished by releasingthe “trigger” wire or tether wire(s). The limitation of this design isthe lack of ability to reduce the diameter of the entire length of stentby stretching the stent which is pursed down on the distal end by thetrigger wire. The significance of reducing the diameter of the stentwhile positioning and determining if it should be released from thetether wire is that the blood flow is occluded by the fully expandedmain body of the stent even while the distal end is held from opening bythe tether wire.

Another disadvantage of conventional stent-grafts is the temporarydisruption in blood flow through the vessel. In the case of balloondeployable stents and stent-grafts, expansion of the balloon itselfwhile deploying the stent or stent-graft causes disruption of blood flowthrough the vessel. Moreover, in certain applications, a separateballoon is used at a location distal to the distal end of the stentdelivery catheter to actively block blood flow while the stent is beingplaced. In the case of self-expanding stent-grafts, the misplacement ofa stent graft may be due to disruption of the arterial flow duringdeployment, requiring the placement of an additional stent-graft in anoverlapping fashion to complete the repair of the vessel. Even withoutdisruptions in flow, the strong momentum of the arterial blood flow cancause a partially opened stent-graft to be pushed downstream by thehigh-pressure pulsatile impact force of the blood entering the partiallydeployed stent graft.

Attempts have been made to address some of the above-describeddisadvantages of conventional stents and stent grafts. For example, U.S.Pat. No. 6,099,548 discloses the use of strings passed through andattached to the distal end of the stent which is inserted through afirst opening in the vasculature. The string ends are then passedthrough a second opening in the vasculature such that they can bepulled, thereby moving the stent within the vasculature. While the useof attached strings provides some additional control of the stent'splacement, one skilled in the art can appreciate that passing stringsfrom within the vasculature through a second opening presents proceduraldifficulties. Moreover, it is advantageous to the welfare of the patientto minimize the number of surgical openings when performing anyprocedure.

With the limitations of current stent grafts and stent graft placementtechnologies, there is clearly a need for an improved means and methodfor implanting a stent or graft and for treating vascular disease andconditions affecting interconnecting vessels (i.e., vascular trees)which address the drawbacks of the prior art.

SUMMARY OF THE INVENTION

The present invention is directed to methods for deploying a stent fortreating a vascular disease. The stent may be constructed of a singlewoven wire with a main lumen having proximal and distal ends and one ormore side branch lumen interconnected with the main lumen. The stent isinserted into a vessel such as that of the aortic arch and by pulling onboth ends of the main lumen the stent is contracted is size. Oncealigned in the desired position one or both of the ends are released andthe stent expands against the inner vessel wall. The stent is left inplace and the extracellular matrix coating the wire provides animmediate temporary repair of a vessel aneurysm and thereafter allowsthe vessel wall to reform and integrate the stent into the vessel for apermanent repair of the vessel aneurysm.

An implantable coated adjustable stent is disclosed which is comprisedof a main lumen having a proximal end and a distal end which lumen isconstructed from a wire bent into a lumen shape and one or more sidebranch lumens also constructed from wire and interconnected to the mainlumen. At least a portion of the stent is coated with an extracellularmatrix. The side branch lumens are adjustable laterally along the lengthof the main lumen relative to the proximal and distal ends and are alsoadjustable in terms of the angle at which they intersect with the mainlumen. The stent is constructed from a super elastic wire material whichhas a first or unreduced dimension “X” and a reduced dimension “Y” whichis anywhere from one half or less to one tenth or less of the firstdimension “X.” For aortic applications, where the dimension is thediameter of the stent, the reduced diameter is more likely to be closerto one tenth of the unreduced diameter. The smaller the vessel intowhich the stent is to be implanted, the smaller the necessary reductionin diameter.

The implantable coated stent of the invention can be loaded into thetubular opening of a catheter. The catheter can be inserted inside thevessel and placed at an appropriate site where the stent can bedeployed. Upon being deployed the stent position can be adjusted bymeans of a plurality of strings detachably connected to the stent. Oncein place the stent coating of extracellular matrix material aids inintegrating the stent into the vessel wall. The stent is in its reducedshape when inside the catheter and expands inside the vessel to anexpanded shaped which applies pressure thereby opening the vesselchannels. By integrating the stent into the vessel using theextracellular matrix problems with rejection as well as new blockagesappearing are reduced.

The implantable devices of the present invention include at least a mainlumen having a proximal end and a distal end, but often includes atleast one side branch lumen to address implant sites havinginterconnecting vessels. The devices, particularly in the form ofstents, grafts and stent grafts, are made of interconnected cells whichmay be selectively manipulated to adjust the length and diameter of themain and side branch lumens of the devices. As such, a feature of thepresent invention is the provision of a variable or adjustable stent,grafts or stent graft that is able to address inconsistent orpatient-to-patient variabilities in tortuous vascular anatomies, e.g.,to accommodate variability in the spacing between or the angularorientation of the tributary vessels of the aortic arch.

The systems of the present invention are particularly suitable fordelivering and deploying the subject stent, graft or stent graft deviceswithin a vessel or tubular structure within the body, particularly wherethe implant site involves two or more interconnecting vessels. Ingeneral, the delivery and deployment system of the present inventionutilizes at least one elongated member or string, and in manyembodiments a plurality of elongated members or strings which arereleasably attached to the luminal ends of the implantable device. Asingle string or a set of attachment strings is provided for each of theproximal and distal ends of the main lumen of the device and anadditional string or set of strings is provided for each side branchlumen. The system includes means for selectively tensioning each of thesingle or plurality of attachment strings whereby the device isselectively deployable by releasing the tension on the attachmentstrings. The delivery system controls the adjustment of spacing betweenthe various lumens and their respective angular radial orientation withrespect to the main lumen to be varied in situ during placement of theimplant at the target location. There may be other means equallysuitable for selective deployment of the stent beyond the use ofdetachable strings. For example, similar to the use of detachable coilsused in aneurysm repair, a current may be used to erode by electrolysisthe connection point to the stent ends. In other words, the implantabledevice may be partially deployable, where the entirety of the device isexposed or partially exposed from the delivery system, which is mostcommonly in the form of a collection of nested catheters and lumens.Each luminal end of the implantable device may be individually deployedas desired, where some or all of the luminal ends may be simultaneouslydeployed or they may be serially deployed in an order that bestfacilitates the implantation procedure.

The implant delivery and deployment system in one embodiment includes aseries of guidewires, a distal catheter portion and a proximal handleportion where the implantable device is loaded within the catheterportion prior to delivery to the target site. At least the catheterportion of the system is tracked over the one or more guidewires whichdirect and position the stent or stent-graft and each of its brancheswithin their respective targeted vessels selected for implantation.Various controls are provided for the selective tensioning and releaseof the implant's luminal ends, where the controls may be located on thehandle portion, the catheter portion or both. In a preferred embodiment,the catheter portion and/or the delivery guidewires are articulatable attheir distal ends to facilitate navigation through the vasculature.

One embodiment of the system includes an articulating delivery guidewireor guiding catheter. The articulating guidewire may have one or morearticulation points to allow an operator to change the shape of thedistal portion of the guidewire by manipulation of the proximal portionof the guidewire. The guidewire can be preconfigured to change from astraight configuration into a range of various preselected shapesbrought about by controlling individual articulation points duringmanipulation of the proximal portion of the guidewire. In this way, aguidewire may be produced to unique specifications for access todistinct areas of the vasculature. For example, this may be ofparticular importance in locating the implant within a region thatrequires an “S” shaped path from entry point to implant target site.Introduction of a guidewire through a femoral artery access pointleading to an implant target in the innominate artery exemplifies oneinstance of a potentially difficult “S” shaped navigation pathway wheresuch an articulating guidewire may be advantageous.

The methods of the present invention involve deploying the implantabledevice where certain of the methods involve the use of the subjectsystems. Methods for manufacturing the implantable devices are alsoprovided.

Another objective of the invention is to provide a method of stentdeployment which does not cause temporary occlusion of the vessel intowhich stent is to be placed.

Another objective of the invention is to provide a method of stentdeployment using guidewires and an associated delivery system whichenter the vasculature from a single access location.

An advantage of the stent delivery system of the present invention isthat it does not require the use of space-occupying stylets and ballooncatheters.

Another advantage of the subject system is that it allows for adjustmentof the position or placement, as well as removal, of a stent during andafter deployment thereof.

The present invention is additionally advantageous in that it provides auser with the ability to deploy a stent, to evaluate the suitability ofthe resulting deployment using standard imaging, such as by use ofradiographic dye and fluoroscopy or any other imaging system, to checkfor endoleak between the covered stent wall and the surrounding arterialwall and to detach the stent from the delivery system upon adequatestent deployment or, in the case of an inadequate deployment, to eitherrelocate the stent to a new location and obtain a satisfactory result bycontrolling the delivery and detachment of the stent in a repeatablemanner, or to remove the stent entirely.

The present invention is additionally advantageous in that it securesthe stent from migration within the vasculature by integrating the cellsof the side branch lumen into the cells of the main body lumen suchthat, when the side branch lumens are deployed within their branchvessels, the main body lumen is constrained from migration by a “lockand key” mechanism. More specifically, the interconnection of the sidebranch lumen to the main body lumen is accomplished by forming the sidebranch lumen and the main body lumen from the same single wire where aspecific wire wrap pattern is used to form a linking mesh to integratethe side branch lumen with the main lumen. Thus, when the side branch isdeployed within and held in place by the side branch artery, the mainbody of the stent cannot migrate. Moreover, such a “passive” anchoringmechanism is atraumatic, as opposed to an active anchoring means, suchas barbs or hooks, which may damage the cellular structures of theimplant site leading to smooth muscle proliferation, restenosis, andother vascular complications.

These and other objects, advantages, and features of the invention willbecome apparent to those persons skilled in the art upon reading thedetails of the invention as more fully described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in conjunction with the accompanying drawings. It isemphasized that, according to common practice, the various features ofthe drawings are not to-scale. On the contrary, the dimensions of thevarious features are arbitrarily expanded or reduced for clarity. Alsofor purposes of clarity, certain features of the invention may not bedepicted in some of the drawings. Included in the drawings are thefollowing figures:

FIG. 1A illustrates an embodiment of an implant of the present inventionin a natural, deployed state.

FIG. 1B illustrates another embodiment of an implant of the presentinvention in a natural, deployed state.

FIG. 1C illustrates another embodiment of an implant in which the sidebranch lumens are angled.

FIG. 1D illustrates an end view of the implant of FIG. 1C.

FIG. 1E illustrates another embodiment of an implant of the presentinvention having a cardiac valve operatively coupled to it.

FIG. 2A is a perspective view of a system of the present invention fordelivering and deploying the implants of the present invention within atubular tissue structure within the body.

FIG. 2B is an enlarged perspective view of the portion of the system ofFIG. 2A including a side branch control and catheter hubs.

FIGS. 3A and 3B are side views of the side branch control and catheterhubs of the system of FIGS. 2A and 2B in open and closed configurations,respectively.

FIG. 4 is a side view of the handle portions of the system of FIG. 2A.

FIG. 5A is a side view of the distal end of the delivery and deploymentsystem of the present invention with an implantable device of thepresent invention shown partially deployed from the implantation system.

FIG. 5B shows a top view of the system and implantable device of FIG.5A.

FIG. 5C shows a longitudinal cross-sectional view of FIG. 5B.

FIG. 6A is a cross-sectional view taken along line A-A of FIG. 5C.

FIG. 6B is a cross-sectional view taken along line B-B of FIG. 5C.

FIG. 6C is longitudinal cross-sectional view of the catheter tip portionof the delivery and deployment system of FIG. 5C.

FIGS. 7A, 7B and 7C are cross-sectional views of possible embodiments ofside branch catheters of the present invention.

FIGS. 8A-8H illustrate various steps of a method of the presentinvention for delivering a stent of the present invention using animplantation system of the present invention.

FIG. 9 illustrates another embodiment of handle portion of the deliveryand deployment system of the present invention.

FIG. 10A illustrates a side view of an embodiment of an inner member ofthe catheter portion of the delivery and deployment system of thepresent invention.

FIG. 10B illustrates a cross-sectional view of the inner member of FIG.10A taken along the line B-B of FIG. 10A.

FIG. 10C illustrates a cross-sectional view of the inner member of FIG.10 taken along the line C-C of FIG. 10A.

FIG. 11 illustrates the partial deployment of the implant of FIG. 1Ewithin the aortic root.

FIGS. 12A-12F illustrate various steps of another method of the presentinvention for delivering a stent of the present invention using animplantation system of the present invention.

FIGS. 13A-13C illustrate various exemplary mandrel designs forfabricating the stents and stent grafts of the present invention.

FIG. 14 illustrates an exemplary wire winding pattern to form a stent ofthe present invention.

FIG. 15 illustrates one manner in grafting a stent of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Before the devices, systems and methods of the present invention aredescribed, it is to be understood that this invention is not limited toparticular therapeutic applications and implant sites described, as suchmay vary. It is also to be understood that the terminology used hereinis for the purpose of describing particular embodiments only, and is notintended to be limiting, since the scope of the present invention willbe limited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The terms “proximal” and“distal” when used to refer to the delivery and deployment systems ofthe present invention are to be understood to indicate positions orlocations relative to the user where proximal refers to a position orlocation closer to the user and distal refers to a position or locationfarther away from the user. When used with reference to the implantabledevices of the present invention, these terms are to be understood toindicate positions or locations relative to a delivery and deploymentsystem when the implantable devices is operatively positioned within thesystem. As such, proximal refers to a position or location closer to theproximal end of the delivery and deployment system and distal refers toa position or location closer to the distal end of the delivery anddeployment system. The term “implant” or “implantable device” as usedherein includes but is not limited to a device comprising a stent, agraft, a stent-graft or the like.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “astring” may include a plurality of such strings and reference to “thetubular member” includes reference to one or more tubular members andequivalents thereof known to those skilled in the art, and so forth.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassedwithin the invention. The upper and lower limits of these smaller rangesmay independently be included or excluded in the range, and each rangewhere either, neither or both limits are included in the smaller rangesis also encompassed within the invention, subject to any specificallyexcluded limit in the stated range. Where the stated range includes oneor both of the limits, ranges excluding either or both of those includedlimits are also included in the invention.

All publications mentioned herein are incorporated herein by referenceto disclose and describe the methods and/or materials in connection withwhich the publications are cited. The publications discussed herein areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the present invention is not entitled to antedate such publicationby virtue of prior invention. Further, the dates of publication providedmay be different from the actual publication dates which may need to beindependently confirmed. The present invention will now be described ingreater detail by way of the following description of exemplaryembodiments and variations of the devices, systems and methods of thepresent invention. The invention generally includes an implantabledevice which includes a tubular member in the form of a stent, a graftor a stent graft, where the device may further include one or morebranching or transverse tubular members laterally extending from themain or primary tubular member. The invention further includes a systemfor the percutaneous, endovascular delivery and deployment of theimplantable device at a target implant site within the body. The implantsite may be any tubular or hollow tissue lumen or organ; however, themost typical implant sites are vascular structures, particularly theaorta. A feature of the invention is that it addresses applicationsinvolving two or more intersecting tubular structures and, as such, isparticularly suitable in the context of treating vascular trees such asthe aortic arch and the infrarenal aorta.

Implantable Devices of the Present Invention

Referring now to the figures and to FIGS. 1A and 1B in particular, thereare illustrated exemplary embodiments of implantable devices of thepresent invention. Each of the devices has a primary or main tubularmember and at least one laterally extending tubular branch, however, theimplantable devices of the present invention need not have sidebranches.

FIG. 1A illustrates one variation of an implantable device 2 having aprimary tubular portion, body or member 4 and laterally extending sidebranches 6 a, 6 b and 6 c, interconnected and in fluid communicationwith main body 4 by way of lateral openings within the body. Theproximal and distal ends of the main tubular member 4 terminate incrowns or apexes 8, the number of which may vary. The distal ends of theside branches 6 a, 6 b and 6 c terminate in crowns or apexes 10 a, 10 band 10 c, respectively, the number of which may also vary. Device 2 isparticularly configured for implantation in the aortic arch whereprimary tubular member 4 is positionable within the arch walls andtubular branches 6 a, 6 b and 6 c are positionable within the innominateartery, the left common carotid artery and the left subclavian artery,respectively.

As will be described in greater detail below, the deployment orattachment members of the subject delivery and deployment systems, arelooped through the apexes 10 a, 10 b and 10 c, or through eyelets (notshown) extending from the distal ends of the apexes of the device 2. Theattachment members of the present invention may be any elongated memberincluding but not limited any strings, filaments, fibers, wires,stranded cables, tubings or other elongated member which are releasablyattachable to the distal ends of the various lumens of the stent. Meansof releasable attachment include but are not limited to electrolyticerosion, thermal energy, magnetic means, chemical means, mechanicalmeans or any other controllable detachment means.

FIG. 1B illustrates another variation of a device 12 having a primarytubular portion or member 14 and laterally extending branches 16 a and16 b, interconnected and in fluid communication with main body 14 by wayof lateral openings within the body. The proximal and distal ends of themain tubular member 14 terminate in crowns or apexes 18 which areemployed as described above with respect to FIG. 1A while the distalends of the side branches 16 a and 16 b terminate in crowns or apexes 28a and 18 b, respectively. Device 12 is particularly configured forimplantation in the infra-renal aorta where primary tubular member 14 ispositionable within the walls of the aorta and tubular branches 16 a and16 b are positioned within the right and left renal arteries,respectively.

Those skilled in the art will recognize that the subject implants mayhave any number and configuration of lumens (e.g., a single main lumenwithout side branch lumens, a main lumen and one or more side branchlumens) where the one or more side branch lumens may be positioned atany appropriate location along the length of the main lumen and at anyangle with respect to the longitudinal axis of the main lumen, and wherethe there are two or more side branch lumens, the lumens may be spacedaxially and circumferentially angled relative to each other toaccommodate the target vasculature into which the implant is to beplaced. Additionally, the length, diameter and shape (e.g., radius ofcurvature) of each of the implant's lumens may vary as needed toaccommodate the vessel into which it is positioned. Typically, the mainbranch lumen will have an unconstrained length in the range from about 1cm to about 25 cm and an unconstrained diameter in the range from about2 mm to about 42 mm. The side branch lumens will have an unconstrainedlength in the range from about 0.5 cm to about 6 cm and an unconstraineddiameter in the range from about 2 mm to about 12 mm. For example, foraortic applications, the unconstrained length of the main lumen istypically from about 8 cm to about 25 cm and the unconstrained diameteris in the range from about 15 mm to about 42 mm; and the side branchlumens will have an unconstrained length in the range from about 2 cm toabout 6 cm and an unconstrained diameter in the range from about 5 mm toabout 12 mm. For renal applications, the main branch lumen will have anunconstrained length in the range from about 2 cm to about 5 cm and anunconstrained diameter in the range from about 3 mm to about 9 mm; andthe side branch lumens will have an unconstrained length in the rangefrom about 0.5 cm to about 3 cm and an unconstrained diameter in therange from about 2 mm to about 7 mm. For coronary applications, the mainbranch lumen will have an unconstrained length in the range from about 1cm to about 3 cm and an unconstrained diameter from about 2.0 mm toabout 5 mm; and the side branch lumens will have an unconstrained lengthin the range from about 0.5 cm to about 3 cm and an unconstraineddiameter in the range from about 2 mm to about 5 mm. For applications insmaller vessels, such as the neurovasculature, these dimensions will ofcourse be smaller. The various structural and functional aspects of theinventive implants are discussed in greater detail below.

It is also contemplated that therapeutic or diagnostic components ordevices may be integrated with the subject implants. Such devices mayinclude but are not limited to prosthetic valves, such as cardiac valves(e.g., an aortic or pulmonary valve) and venous valves, sensors tomeasure flow, pressure, oxygen concentration, glucose concentration,etc., electrical pacing leads, etc. For example, as illustrated in FIG.1E, an implant 210 for treating the aortic root is provide whichincludes a mechanical or biological prosthetic valve 216 employed at adistal end of the main lumen 212. Device 210 further includes twosmaller, generally opposing side branch lumens 214 a and 214 badjustably aligned for placement within the right and left coronaryostia, respectively. The length of the stent graft may be selected toextend to a selected distance where it terminates at any location priorto, within or subsequent to the aortic arch, e.g., it may extend intothe descending aorta. Any number of additional side branches may beprovided for accommodating the aortic arch branch vessels.

Those skilled in the art will appreciate that any suitable stent orgraft configuration may be provided to treat other applications at othervascular locations at or near the intersection of two or more vessels(e.g., bifurcated, trifurcated, quadrificated, etc.) including, but notlimited to, the aorto-illiac junction, the femoral-popiteal junction,the brachycephalic arteries, the posterior spinal arteries, coronarybifurcations, the carotid arteries, the superior and inferior mesentericarteries, general bowel and stomach arteries, cranial arteries andneurovascular bifurcations.

As mentioned above, the implantable devices of the present invention mayinclude a stent or a graft or a combination of the two, referred to as astent graft, a stented graft or a grafted stent. The stents and graftsof the present invention may be made of any suitable materials known inthe art. Preferably, the stent is constructed of wire, although anysuitable material may be substituted. The wire stent should beelastically compliant, for example, the stent may be made of stainlesssteel, elgiloy, tungsten, platinum or nitinol but any other suitablematerials may be used instead of or in addition to these commonly usedmaterials.

The stents may have any suitable wire form pattern or may be cut from atube or flat sheet. In one embodiment, the entire stent structure isfabricated from a single wire woven into a pattern of interconnectedcells forming, for example, a closed chain link configuration. Thestructure may have a straight cylindrical configuration, a curvedtubular configuration, a tapered hollow configuration, have asymmetricalcell sizes, e.g., cell size may vary along the length or about thecircumference of the stent. In certain stent embodiments, the cell sizeof the side branches lumens is gradually reduced in the distaldirection. This further facilitates the ability to selectively stretchthe distal most portion of the side branch lumens and, thus, making iteasier for a physician to guide the distal end of the side branch into adesignated vessel. The ends of the main stent lumen and/or the end ofone or more side branch stent lumens may be flared. The struts of thestent (i.e., the elemental portions that form a cell) may vary indiameter (in wire embodiments) or thickness or width (in sheet and cuttube embodiments).

In one particular embodiment, the stent is configured from asingle-wire. The single-wire stent configuration is advantageous in thatthrough selective interlacing of the connection points along the lengthof the stent, it provides for adjustability in the angular orientationof the side branch stents relative to each other and relative to themain stent lumen within a selected range that can accommodate anypossible variation in the anatomy being treated. Such angularorientation of the side branch lumens may be axial, circumferential orboth. FIG. 1C illustrates an implant device 20 in which side branchlumens 24 and 26 each has an angular orientation, defined by angle α,with respect to main lumen 22, and have an angular orientation, definedby angle β, with respect to each other. FIG. 1D is an end view ofimplant device 20 which illustrates the circumferential orientation,defined by angle θ, between side branch lumens 22 and 24. Typical rangesof the various angles are as follows: from about 10° to about 170° forangle α, from 0° to about 170° for angle β, and from 0° to 360° forangle θ. These orientations may be provided by the fabrication processresulting in a stent which has naturally biased orientations in anunconstrained, pre-deployed condition, i.e., the neutral state. One ormore of these orientations may be selectively adjusted within the angleranges provided above upon delivery and placement of the branch lumenswithin the respective vessel lumens. This design also allows foradjustability in the linear spacing between the side branch stents bystretching and/or foreshortening of the main lumen of the stent.Further, the side branch portions can be elongated to allow forplacement of an oversized stent in a smaller branch vessel therebyproviding adequate apposition between the stent and the vessel wall. Itshould be noted that the adjustability of the stent does not compromisethe radial force needed to fixate or anchor and prevent migration andendoleak of the stent and/or stent-graft.

The graft portion of a stent graft may be made from a textile, polymer,latex, silicone latex, polyetraflouroethylene, polyethylene, Dacronpolyesters, polyurethane or other or suitable material such asbiological tissue. Biological tissues that may be used include, but arenot limited to, extracellular matrices (ECMs), acellularized uterinewall, decellularized sinus cavity liner or membrane, acellular ureturemembrane, umbilical cord tissue and collagen. Extracellular matricessuitable for use with the present invention include mammalianintestinal, stomach, bladder submucosa, dermis or liver basementmembranes derived from sheep, bovine, porcine or any suitable mammal.The graft material must be flexible and durable in order to withstandthe effects of installation and usage. One of skill in the art wouldrealize that grafts of the subject invention may be formulated by manydifferent well known methods such as for example, by weaving or formedby dipping a substrate in the desired material.

Submucosal tissues (ECMs) of warm-blooded vertebrates are useful intissue grafting materials. For example, submucosal tissue graftcompositions derived from small intestine have been described in U.S.Pat. No. 4,902,508 (hereinafter the '508 patent) and U.S. Pat. No.4,956,178 (hereinafter the '178 patent), and submucosal tissue graftcompositions derived from urinary bladder have been described in U.S.Pat. No. 5,554,389 (hereinafter the '389 patent). All of these (ECMs)compositions are generally comprised of the same tissue layers and areprepared by the same method, the difference being that the startingmaterial is small intestine on the one hand and urinary bladder on theother. The procedure detailed in the '508 patent, incorporated byreference in the '389 patent and the procedure detailed in the '178patent, includes mechanical abrading steps to remove the inner layers ofthe tissue, including at least the luminal portion of the tunica mucosaof the intestine or bladder, i.e., the lamina epithelialis mucosa(epithelium) and lamina propria, as detailed in the '178 patent.Abrasion, peeling, or scraping the mucosa delaminates the epithelialcells and their associated basement membrane, and most of the laminapropria, at least to the level of a layer of organized dense connectivetissue, the stratum compactum. Thus, the tissue graft material (ECMs)previously recognized as soft tissue replacement material is devoid ofepithelial basement membrane and consists of the submucosa and stratumcompactum.

The (ECMs) epithelial basement membrane may be in the form of a thinsheet of extracellular material contiguous with the basilar aspect ofepithelial cells. Sheets of aggregated epithelial cells of similar typeform an epithelium. Epithelial cells and their associated epithelialbasement membrane are positioned on the luminal portion of the tunicamucosa and constitute the internal surface of tubular and hollow organsand tissues of the body. Epithelial cells and their associatedepithelial basement membrane are also positioned on the external surfaceof the body, i.e., skin. Examples of a typical epithelium having abasement membrane include, but are not limited to the following: theepithelium of the skin, intestine, urinary bladder, esophagus, stomach,cornea, and liver.

Epithelial cells are positioned on the luminal or superficial side ofthe epithelial basement membrane, opposite to connective tissues.Connective tissues, the submucosa, for example, are positioned on theabluminal or deep side of the basement membrane. Examples of connectivetissues used to form the ECMs that are positioned on the abluminal sideof the epithelial basement membrane are the submucosa of the intestineand urinary bladder, and the dermis and subcutaneous tissues of theskin. All of these materials are referred to here as ECMs orextracellular matrix material and can be used to coat all or any part ofthe stent.

The stent may be coated with or anchored mechanically to the graft, forexample, by physical or mechanical means (e.g., screws, cements,fasteners, such as sutures or staples) or by friction. Further,mechanical attachment means may be employed to effect attachment to theimplant site by including in the design of the stent a means forfastening it into the surrounding tissue. For example, the device mayinclude metallic spikes, anchors, hooks, barbs, pins, clamps, or aflange or lip to hold the stent in place.

The stent may be processed in such a way as to adhere a covering, suchas made of an ECM material, to only the wire, and not extend betweenwire segments or within the stent cells. For instance, one could applyenergy in the form of a laser beam, current or heat to the wire stentstructure while the ECM has been put in contact with the underlyingstructure. Just as when cooking meat on a hot pan leaves tissue, the ECMcould be applied to the stent in such a manner.

The subject stents, grafts and/or stent grafts may be coated in order toprovide for local delivery of a therapeutic or pharmaceutical to thedisease site. Local delivery requires smaller dosages of therapeutic orpharmaceutical delivered to a concentrated area; in contrast to systemicdosages which require multiple administrations and loss of materialbefore reaching the targeted disease site.

The submucosa tissue may have a thickness of about 80 micrometers, andconsists primarily (greater than 98%) of a cellular, eosinophilicstaining (H&E stain) extracellular matrix material. Occasional bloodvessels and spindle cells consistent with fibrocytes may be scatteredrandomly throughout the tissue. Typically the UBS is rinsed with salineand optionally stored in a frozen hydrated state until used.

Fluidized UBS can be prepared in a manner similar to the preparation offluidized intestinal submucosa, as described in U.S. Pat. No. 5,275,826the disclosure of which is expressly incorporated herein by reference.The UBS is comminuted by tearing, cutting, grinding, shearing and thelike. Grinding the UBS in a frozen or freeze-dried state is preferredalthough good results can be obtained as well by subjecting a suspensionof submucosa pieces to treatment in a high speed (high shear) blenderand dewatering, if necessary, by centrifuging and decanting excesswater. Additionally, the comminuted fluidized tissue can be solubilizedby enzymatic digestion of the bladder submucosa with a protease, such astrypsin or pepsin, or other appropriate enzymes for a period of timesufficient to solubilize said tissue and form a substantiallyhomogeneous solution.

The coating for the stent may be powder forms of UBS. In one embodimenta powder form of UBS is prepared by pulverizing urinary bladdersubmucosa tissue under liquid nitrogen to produce particles ranging insize from 0.1 to 1 mm². The particulate composition is then lyophilizedovernight and sterilized to form a solid substantially anhydrousparticulate composite. Alternatively, a powder form of UBS can be formedfrom fluidized UBS by drying the suspensions or solutions of comminutedUBS.

The subject stents, grafts and/or stent grafts are coated by applying aprimer layer onto its surface. The primer layer formulates a reservoirfor containing the therapeutic/pharmaceutical. The overlapping regionbetween the primer layer and active ingredient may be modified toincrease the permeability of the primer layer to the active ingredient.For example, by applying a common solvent, the active ingredient and thesurface layer mix together and the active ingredient gets absorbed intothe primer layer. In addition, the primer layer may also be treated toproduce an uneven or roughened surface. This rough area entraps theactive ingredient and enhances the diffusion rate of the ingredient whenthe stent is inserted into the patient's body. As such, the implant hasthe ability to diffuse drugs or other agents at a controllable rate.Furthermore, one of skill in the art would understand that the subjectinvention may provide a combination of multiple coatings, such as theprimer lay may be divided into multiple regions, each containing adifferent active ingredient.

The subject stents, grafts and/or stent grafts may be coated with anytherapeutic material, composition or drug, including but not limited to,dexamethasone, tocopherol, dexamethasone phosphate, aspirin, heparin,coumadin, urokinase, streptokinase and TPA, or any other suitablethrombolytic substance to prevent thrombosis at the implant site.Further therapeutic and pharmacological agents include but are notlimited to tannic acid mimicking dendrimers used as submucosastabilizing nanomordants to increase resistance to proteolyticdegradation as a means to prevent post-implantational aneurysmdevelopment in decellularized natural vascular scaffolds, cell adhesionpeptides, collagen mimetic peptides, hepatocyte growth factor,proliverative/antimitotic agents, paclitaxel, epidipodophyllotoxins,antibiotics, anthracyclines, mitoxantrone, bleomycins, plicamycin, andmitomycin, enzymes, antiplatelet agents, non-steroidal agents,heteroaryl acetic acids, gold compounds, immunosuppressives, angiogenicagents, nitric oxide donors, antisense oligonucleotides, cell cycleinhibitors, and protease inhibitors.

The subject implants may also be seeded with cells of any type includingstem cells, to promote angiogenesis between the implant and the arterialwalls. Methods have included applying a porous coating to the devicewhich allows tissue growth into the interstices of the implant surface.Other efforts at improving host tissue in growth capability and adhesionof the implant to the host tissue have involved including anelectrically charged or ionic material in the tissue-contacting surfaceof the device. As mentioned earlier, the subject stents and grafts mayalso be provided with a covering or otherwise be implanted or embeddedwith or be completely fabricated from an extracellular matrix (ECM)material. Suitable ECM materials are derived from mammalian hostssources and include but are not limited to small intestine submucosa,liver basement membrane, urinary bladder submucosa, stomach submucosa,the dermis, etc. Other examples of ECM material includes but is notlimited to fibronectin, fibrin, fibrinogen, collagen, includingfibrillar and non-fibrillar collagen, adhesive glycoproteins,proteoglycans, hyaluronan, secreted protein acidic and rich in cysteine(SPARC), thrombospondins, tenacin, and cell adhesion molecules, andmatrix metalloproteinase inhibitors.

The ECM portion of the implant is eventually resorbed by the surroundingtissue, taking on the cellular characteristics of the tissue, e.g.,endothelium, smooth muscle, adventicia, into which it has been resorbed.Still yet, an ECM scaffolding having a selected configuration may beoperatively attached to a stent or stent graft of the present inventionat a selected location whereby the ECM material undergoes subsequentremodeling to native tissue structures at the selected location. Forexample, the ECM scaffolding may be positioned at the annulus of apreviously removed natural aortic valve configured in such a way as tocreate the structural characteristics of aortic valve leaflets andwhereby the implant provides valve function.

The stent, graft, or stent graft of the present invention may alsoinclude a sensor or sensors to monitor pressure, flow, velocity,turbidity, and other physiological parameters as well as theconcentration of a chemical species such as for example, glucose levels,pH, sugar, blood oxygen, glucose, moisture, radiation, chemical, ionic,enzymatic, and oxygen. The sensor should be designed to minimize therisk of thrombosis and embolization. Therefore, slowing or stoppage ofblood flow at any point within the lumen must be minimized. The sensormay be directly attached to the outer surface or may be included withina packet or secured within the material of the stent, graft, or stentgraft of the present invention. The biosensor may further employ awireless means to deliver information from the implantation site to aninstrument external to the body.

The stent, graft or stent graft may be made of visualization materialsor be configured to include marking elements, which provide anindication of the orientation of the device to facilitate properalignment of the stent at the implant site. Any suitable materialcapable of imparting radio-opacity may be used, including, but notlimited to, barium sulfate, bismuth trioxide, iodine, iodide, titaniumoxide, zirconium oxide, metals such as gold, platinum, silver, tantalum,niobium, stainless steel, and combinations thereof. The entire stent orany portion thereof may be made of or marked with a radiopaque material,i.e., the crowns of the stent.

Device Fabrication Methods

The stent of the present invention may be fabricated in many ways. Onemethod of making the stent is by use of a mandrel device such as themandrel devices 320, 330 and 340 illustrated in FIGS. 13A-13C,respectively. Each of the devices has at least a main mandrel component322, 332 and 342, respectively, with a plurality of selectivelypositioned pinholes 324, 334 and 344, respectively, within which aplurality of pins (not shown) are selectively positioned, or from whicha plurality of pins is caused to extend. As is described in more detailbelow, the stent structure is formed by selectively wrapping a wirearound the pins. Where the stent is to have one or more side branchlumens, the mandrel device, such as device 340, may be provided with atleast one side mandrel 346 extending substantially transverse to themain mandrel 342, where the number of side mandrels preferablycorresponds to the number of stent side branches to be formed. Themandrel devices may be modular where side branch mandrels of varyingdiameters and lengths can be detachably assembled to the main mandrel.The configuration of the main mandrel as well as the side branchmandrel(s) may have any suitable shape, size, length, diameter, etc. toform the desired stent configuration. Commonly, the mandrel componentshave a straight cylindrical configuration (see FIGS. 13A and 13C) havinga uniform cross-section, but may be conical with varying diameters alonga length dimension (see FIG. 13B), frustum conical, have an ovalcross-section, a curved shape, etc.

The pins may be permanently affixed to the mandrel components or arethemselves removable from and selectively positionable within holesformed in the mandrel components. Still yet, the mandrel device may beconfigured to selectively extend and retract the pins. The number ofpins and the distance and spacing between them may be varied to providea customized pin configuration. This customization enables thefabrication of stents having varying sizes, lengths, cell sizes, etc.using a limited number of mandrel components. For example, in onevariation, the pins are arranged about the mandrel components in analternating pattern such as for example, where four out of eight pinholes per row will be filled with pins. Alternatively, a selection ofmandrels may be provided, each having a unique pinhole pattern which inturn defines a unique stent cell pattern.

To form the stent, a shape memory wire, such as a NITINOL wire, having aselected length and diameter are provided. Typically, the length of thewire ranges from about 9 to about 12 feet long, but may be longer ifneeded or shorter if more practical. The wire's diameter is typically inthe range from about 0.001 to about 0.020 inch. After providing amandrel device having winding pins at the desired points or locations onthe mandrel components, the wire is wound about the pins in a selecteddirection and in a selected over-and-under lapping pattern, e.g., azigzag pattern, to form a series of interconnected undulated ringsresulting in a desired cell pattern.

An exemplary wire winding pattern 350 is illustrated in FIG. 14.Starting from one end of the main mandrel, the wire 352 is wound aroundthe pins 354 in a zigzag pattern back and forth from one end of the mainmandrel to the other until the cells of the main lumen of the stent havebeen formed. Next, the same wire, still attached to the mandrel device,is used to form the side branch lumen(s) where the wire is wrapped in azigzag fashion from the base of the side branch mandrel to the distallyextending end and back again until all of the cells of the side branchhave been created. Then the wire is wound about the main mandrel along apath that is at an angle to longitudinal axis of the main mandrel wherethe wire is doubled over itself along certain cell segments 356. Itshould be noted that any lumen of the stent may be fabricated first,followed by the others, or the winding pattern may be such that portionsof the various lumens are formed intermittently.

The mandrel device with the formed wire stent pattern are then heated toa temperature in the range from about 480° C. to about 520° C. andtypically to about 490° C. for approximately 20 minutes, however, thistime may be reduced by using a salt bath. The duration of theheat-setting step is dependent upon the time necessary to shift the wirematerial from a Martensitic to an Austenitic phase. The assembly is thenair cooled or placed into a water bath to quench for 30 seconds or moreand then allowed to air dry. Once the stent is sufficiently dried, thepins are either pulled from the mandrel device or retracted into thehollow center of the mandrel by an actuation of an inner piece whichprojects the pins out their respective holes in the outer surface of themandrel. The stent with its interconnected lumens can then be removedfrom the mandrel device. Alternatively, with the mandrel componentsdetached from one another, one of the lumens, e.g., the main stentlumen, may be formed first followed by formation of a side branch lumenafter attachment of a side mandrel to the main mandrel.

Optionally, selected regions of the main body or the portions of thewire forming the side branch lumen cells may be selectively reduced indiameter by etching or e-polishing so as to exert less radial force thanthat wire portion of the stent that has not been reduced in wirediameter. One example of a selective reduction of wire diameter in themain body of the stent is to leave a one to two centimetercircumferential portion on each of the proximal and distal ends to allowhigh radial force at those regions to secure the stent from migrationwhile the center portion between those high radial force regions can bereduced in cross sectional wire diameter in order to facilitatestretching the stent more easily during placement or allowing it tocompact into the delivery sheath more easily over a long length. Anotherexample of selectively reducing the wire cross sectional diameter is tomake the struts of the side branch smaller in diameter. This can be doneby selective immersion of the side branch in an acid during manufactureto reduce the amount of metal in a particular region of the stent.Another method to accomplish the desired result of preferentiallyreducing side branch longitudinal stiffness and/or outward radial forceof the side branch component is to use an electropolishing apparatus. Byplacing the woven solid wire stent into an electrolyte bath and applyinga voltage potential across an anode-cathode gap, where the stent itselfis the anode, metal ions are dissolved into the electrolytic solution.Alternatively, or subsequently, the process may be reversed wherein thestent becomes the cathode and the side branch or other selected regionof the stent may be electroplated with a similar or different metal inionic solution, for instance gold or platinum, in order to either changethe mechanical properties or to enhance the radiopacity of the selectedregion. Those skilled in the art of electroplating and electropolishingwill recognize that there are techniques using a “strike” layer of asimilar material to the substrate in order to enhance the bonding of adissimilar material to the substrate. An example would be the use of apure nickel strike layer on top of a nickel titanium (NITINOL) substratein order to subsequently bond a gold or platinum coating to thesubstrate.

Another method of making the stent is to cut a thin-walled tubularmember, such as stainless steel tubing, to remove portions of the tubingin the desired pattern for the stent, leaving relatively untouched theportions of the metallic tubing which are to form the stent. The stentalso can be made from other metal alloys such as tantalum,nickel-titanium, cobalt-chromium, titanium, shape memory andsuperelastic alloys, and the nobel metals such as gold or platinum.

In accordance with the invention, one of skill in the art would knowthat several different methods may be employed to make the subjectstents such as using different types of lasers; chemical etching;electric discharge machining; laser cutting a flat sheet and rolling itinto a cylinder; all of which are well known in the art at this time.

Where a stent graft 360 is to be formed by the addition of a graftmaterial 362, such as an ECM, to the subject stent 364, any manner ofattaching the graft material to the wire form may be used. In onevariation, the graft material is attached by way of a suture 366. Assuch, one edge 370 of the graft material is stitched lengthwise to thestent frame along the stents length, where at least one knot 368 is tiedat each apex of the stent to secure an end of the graft to the stent.Then the graft material is stretch around the surface of the stent andthe opposite edge 372 of the graft is overlapped with the alreadyattached edge 370 and independently stitched to the stent frame toprovide a leak free surface against which blood cannot escape. The graftmaterial is stretched to an extent to match the compliance of the stentso that it does not drape when the stent is in the expanded state. Uponcomplete attachment of the graft material to the stent, the graft isdehydrated so that it snuggly shrinks onto the stent frame similar toheat shrink tubing would when heated.

Delivery and Deployment Systems of the Present Invention

Referring now to FIGS. 2A and 2B, there is shown a system 30 of thepresent invention for implanting the devices of the present invention.System 30 includes a distal catheter portion 32 and a proximal or handleportion 34. Catheter portion 32 is configured for positioning within thevasculature or other pathway leading to the implant site, and includesvarious elongated members having a plurality of lumens, many of themmulti-functional, for guide wire, pull-wire, and fluid passage from oneend of the device to the other. Catheter portion 32 includes atranslatable outer sheath 38 having a lumen within which an intermediatemember 40 is received. The proximal end of outer sheath 38 is configuredwith a fitting 50 for coupling to a distal hub 52 of intermediateportion 40. Fitting 50 is configured with an internal valve mechanismwhich fluidly seals the luminal space between the walls of outer member38 and intermediate member 40, thereby preventing leakage of bloodtherefrom. Fitting 50 may further include a flush port (not shown) forevacuation of any residual air as is common in catheter preparation. Aninner member 42 is received and translatable within a lumen 138 (seeFIG. 6A) of intermediate member 40 and defines a main body guide wirelumen 44 for translation of a guide wire 48 therethrough. Inner member42 terminates at a conical distal tip 46 which facilitates forwardtranslation of the device through tortuous vasculature. The outermember, intermediate member and inner member tubings (as well as anycatheter components discussed below) may be made from materials used toconstruct conventional intravascular sheaths and catheters, includingbut not limited to biocompatible plastics reinforced with braidedmaterials or any other biocompatible materials which are substantiallyflexible.

The proximal portion 34 of delivery and deployment system 30 includesproximal and distal handle portions 36 a, 36 b which translate axiallywith respect to each other. Inner member 42 is fixed to proximal portion36 a of the handle and intermediate member 40 is fixed to distal portion36 b of the handle such that axial separation and extension of the twohandle portions relative to each other controls the amount of extensionand foreshortening undergone by a stent operatively loaded within thedelivery system, as will be explained in greater detail below.

As mentioned above, the delivery and deployment of an implant of thepresent invention is accomplished by the use of a plurality ofdesignated attachment strings, wires or filaments. A single string or aset or plurality of strings is provided for controlling and releasablyattaching each free end of the implant to the delivery system. Twoseparate strings or sets of strings are employed to control the maintubular portion of an implantable device—one string or set of stringsfor controlling the distal end and the other for controlling theproximal end of the device. For each lateral branch of the implant, anadditional string or set of strings is provided. The number of stringsin each set correlates to the number of crowns or connecting pointsprovided at the respective ends (i.e., at the proximal and distal endsof the main stent portion and at the distal ends of the branch portions)of the device. Each string is interlooped with a designated crown withboth of its ends positioned and controlled at the handle of the device,where one end of each attachment string is permanently affixed to thedelivery and deployment system 30 and the other end is releasablyattachable to the delivery and deployment system 30. When operativelyloaded within system 30, the luminal ends of the implant are releasablyattached to various portions of system 30. For example, the distal endof the main lumen of the stent is releasably attached to inner member42, the proximal end of the main lumen of the stent is releasablyattached to intermediate member 40, and the distal end of each sidebranch stent is releasably attached to a designated side branch catheter150 (see FIG. 6A).

Each attachment string or set of attachment strings is controlled, i.e.,able to be fixed, released, tensioned, pulled, tightened, etc., by adesignated control mechanism. Accordingly, the number of controlmechanisms provided on the illustrated embodiment of the subject systemcorresponds to the number of attachment string sets; however, control ofthe string sets may be consolidated into a fewer number of controlmechanisms. The various control mechanisms may have any suitableconfiguration and be mounted at any suitable location on system 30 whereone exemplary configuration and location of the control mechanisms isillustrated in FIG. 2A. In particular, each control mechanism includes apair of controls in the form of knobs, dials, switches or buttons, forexample, where one control is for linearly translating, i.e., pulling,the strings by their fixed ends through the deployment system 30 whendeploying the implant, and the other control is for selectivelyreleasing and fixing the free ends of the strings prior to deployment ofthe implant.

Controls 70 a, 70 b and 72 a, 72 b, for controlling the distal andproximal luminal ends, respectively, of the implant, are provided onhandle portions 36 a and 36 b, respectively. An additional pair ofcontrols for each set of attachment strings associated with each of theimplant's side or lateral branch lumens is provided on a hub releasablymounted to intermediate member 40 where the collective hubs are seriallyarranged between the proximal end 50 of outer sheath 38 and the distalend of distal handle portion 36 b. For example, for use with implant 2of FIG. 1A having three branch lumens 6 a, 6 b and 6 c, three hubs 74,76 and 78 and associated pairs of controls, respectively, are providedwhere the most distal pair of controls 74 a, 74 b controls theattachment strings for the most distal of the stent branch lumens 6 a,the second or middle pair of controls 76 a, 76 b controls the attachmentstrings for the middle stent branch lumen 6 b, and the most proximalpair of controls 78 a, 78 b controls the attachment strings for the mostproximal of the stent branch lumens 6 c.

Each pair of controls includes a fixed-end member 70 a, 72 a, 74 a, 76 aand 78 a, here in the form of a knob, to which one set, the fixed set,of ends of the attachment strings is permanently anchored but whichitself is removable from the respective handle portion or hub in orderto manually pull the strings therethrough. This control maintains aconstant tension on the attachment strings and keeping the implantrestrained within the delivery system while the delivery system is beingarticulated through the vasculature. As best illustrated in FIG. 2B,each knob is positioned within a hemostatic valve 80 for preventing theback flow of fluid, e.g., blood, out of the handle or hub before andafter the knob is removed therefrom. Each pair of controls also includesa releasable end member or clamp 70 b, 72 b, 74 b, 76 b and 78 b, herein the form of a dial or drive screw, by which the free ends of thestring set are releasably anchored to the respective handle portion orhub. When ready to deploy a respective luminal end of the implant, thedrive screw is selectively loosened to allow for release of the tensionon the respective string set. Those skilled in the art will appreciatethat the relative positioning and arrangement of the various controlmechanisms may vary with the intent of providing an organized,ergonomically designed profile.

Referring now to FIGS. 2B, 3A and 3B, each side branch control hub 74,76 and 78 is associated with a distally positioned side branch catheterhub 84, 86 and 88, respectively (only the most proximally positionedhubs 78 and 88 are illustrated in FIG. 2B). Extending between each pairof hubs is a proximal portion 94 a, 94 b, 94 c of side branch catheters150 a, 150 b, 150 c, respectively (see FIG. 6A), which extends from asealable port 110 a, 110 b, 110 c (see FIG. 2B) at the back end of eachcontrol hub 74, 76 and 78 to a distal end and through respective sidebranch catheter lumens 148 within intermediate member 40 (see FIG. 6A).Within each side branch catheter 150 a, 150 b, 150 c is a side branchguide wire lumen 152 a, 152 b, 152 c (see FIG. 6A). Port 110 a, 110 b,110 c allows for the entry and passage of a side branch guide wire 154a, 154 b, 154 c (see FIG. 6A) through a respective side branch guidewire lumen 152. One or both of the side branch catheter and side branchguidewire may be deflectable. Each of the control hubs 74, 76 and 78 areslidably engaged with intermediate member 40. The undersides of thecontrol hubs have cuff 96, a partial ring configuration or the like,such that hubs are fully releasable from intermediate member 40 as wellas slidable thereon. As mentioned above, each of the side branch stentlumens is releasably coupled to the distal end of side branch catheter150 a, 150 b, 150 c by way of a designated attachment string or set ofattachment strings. Regardless of the relative position between the sidebranch control hubs 74, 76, 78 and the associated side branch catheterhubs 84, 86, 88, the attachment string sets are held in complete tensionin both configurations illustrated in FIGS. 3A and 3B until they arereleased by their respective control knobs 74 b, 76 b, and 78 b. Whenthe control hubs are in a distal or close position relative to thecatheter hubs, as illustrated in FIGS. 2A and 3B, where the proximalportion 94 a, 94 b, 94 c of side branch catheter 150 a, 150 b, 150 c isfully received within the associated catheter hub, the side branchstents are held in a partially deployed state. In the partially deployedstate, the side branch stents are held stretched, with tension beingapplied by the distal end of the respective extended side branchcatheter 94 a, 94 b, 94 c removably attached to the distal end of thestretched side branch stent apices or connection points by the sidebranch catheters' respective string or string set. The tension beingapplied to the distal end of each side branch stent is transferredthrough the side branch stent thereby elongating its length whilesimultaneously reducing the diameter. This allows for the positioning ofa larger stent diameter within a smaller diameter side branch vessel.This partially deployed state, i.e., where the side branch stentdiameter is smaller than the side branch vessel into which it is beingplaced, also allows for the flow of blood around the implant as well asthrough it thereby allowing perfusion of downstream vessels and organsduring placement. It is preferential to have blood continue to flowthrough intersecting side branch vessels during the procedure in orderto avoid ischemia to the effected downstream organs. The side branchstent is stretched by the extension of the side branch catheter which isreleasably attached to the crowns of the distal end of the side branchstent. The stretching of the side branch stent enables its subsequentplacement within an undersized, targeted side branch vessel. Typically,the diameter of a side branch stent in its natural, unconstrained stateis about 5% to about 50% greater than the diameter of the side branchvessel into which it is to be placed. Conversely, when the control hubsare in a proximal or retracted position, as illustrated in FIGS. 2B and3A, each side branch stent is held in a deployed or unstretchedcondition.

The side branch catheters 150 a, 150 b, 150 c slidably extend at theirproximal ends 94 a, 94 b, 94 c through respective side branch catheterhubs 84, 86, 88 and a hemostatic valve 92 a, 92 b, 92 c positioned atthe back end of the catheter hub. Each side branch control hub 74, 76,78 has a luer fitting 110 a, 110 b, 110 c (where only 110 c is shown)which allows a hemostatic valve (not shown) to be applied. Thehemostatic valve may be a Y arm adapter or a Toughy-Borst adapter whichallows the sealed introduction of a guidewire. The Y arm luer fittingallows for clearing the guidewire lumen of air by flushing the catheterwith saline prior to inserting the catheter into the body. At subsequentstages of the procedure, this lumen may be used to introduceradiographic dye in order to visualize blood flow through the sidebranch arteries.

A main body port 76, as illustrated in FIG. 4, located on the back endof proximal handle portion 36 a is in fluid communication with a guidewire lumen 44 which extends through a central lumen 138 (see FIGS. 6Aand 6B) within intermediate member 40. Guide wire lumen 44 provides forthe passage and translation of a primary guide wire 48 which is used todirect and guide distal portion 32 of the system to a target implantsite within the vasculature as well as to facilitate the positioning andimplantation of the distal end of the primary lumen of the implantabledevice. The main body port 76 has a leur fitting similar to leur fitting110 described above with respect to the side branch catheter controlhubs.

As is further illustrated in FIG. 4, a lever mechanism 56 extendingdistally and downwardly from proximal handle portion 36 a is providedfor steering distal catheter portion 32 of device 30 through thevasculature into which it is positioned. This lever may be replaced by arotating control knob 193 in another handle embodiment 194 shown in FIG.9A. A steering pull-wire, string or filament (not shown) is fixed to theproximal end of lever 56 and extends through catheter portion 32 whereits distal end terminates and is attached within nose cone 46 of innermember 42. Lever 56 is pivotally coupled within handle portion 36 a suchthat when rotated in a downward direction (indicated by arrow 65 a ofFIG. 4), the steering pull-wire is caused to be in a relaxed or slackenstate. Conversely, when lever 56 is rotated upward (indicated by arrow65 b), the steering pull-wire is pulled or tensioned thereby causing thedistal tip of inner member 42, and thus the distal end of device 30, tobend. Any number of steering pull-wires may be employed and selectivelytensioned to selectively articulate the distal end of device 30 inmultiple directions orthogonal to the longitudinal axis of theimplantation system. Typically, the subject delivery and deploymentsystem will have at least one, and often two to four distal points ofarticulation. These articulation points may be at one or more distancesfrom the distal end of the catheter 32 in order to create compoundcurves of the distal end of the catheter.

The relative positioning and interfacing of the implantable device withthe various catheters, lumens, guidewires, ports and pull-wires of thesubject implantation system will now be described with respect to FIGS.5A-6C, 6A and 6B. FIGS. 5A-5C illustrate an implantable device 120partially deployed from the distal end 118 of outer sheath 38.Implantable device 120 includes a main tubular body 122 and may includeone or more lateral tubular branches 124. At the distal tips of crownsor apexes 126 of main body 122 and crowns or apexes 128 of side branch124 may be eyelet loops 130 for receiving attachment strings 132 (shownonly in FIG. 5C). Any means of looping the attachment wires to the endof side branch 124 may be used including passing attachment strings orstrings through the windows provided by the cell structure terminatingat an apex. As is illustrated in FIG. 5C, when operatively loaded withinsystem 30 of FIG. 2A, the main lumen 122 of device 120 is longitudinallydisposed between outer sheath 38 and inner member 42 and is positioneddistally of the distal end 134 of intermediate member 40.

To load the implant device into outer sheath 38, the handle controls areset to stretch the stent by extension of the distal tip 46 of the innermember 42 relative to the distal end of the intermediate member. Whenproximal and distal handle portions 36 a and 36 b are extended from eachother, shown in FIG. 8D, the main lumen of the stent is in a stretchedor tensioned condition. Conversely, when proximal and distal handleportions 36 a and 36 b are unextended, as shown in FIG. 8E, the mainlumen of the stent is in an unstretched or untensioned condition. Thedistal lumenal ends of inner member 42 and intermediate member 40 areconnection points for the string or strings which are releasablyattached to the distal and proximal stent main lumen openings 122. Asdiscussed above, the side branch stent distal lumenal end is releasablyattached to the distal end of the side branch catheter.

FIG. 6A shows a cross-section of a distal portion of implantation systemalong the lines A-A of FIG. 5C, specifically, the cross-sectional viewis taken at the distal end of intermediate member 40. This view showsthe nested relationship between outer member 38, intermediate member 40,inner member 42 which is positioned within central lumen 138 ofintermediate member 40, and main guide wire 48 positioned within acentral guide wire lumen 44 of inner member 40 which extends distallythrough tip 46.

Inner member 42 is a very small diameter catheter, for example, in therange of 3 to 8 French for cardiovascular applications, and has, inaddition to central guide wire lumen 44, a plurality of attachmentstring lumens 140 circumferentially disposed about central guide wirelumen 44 which serve to direct the alignment of the attachment stringsto the connection points on the distal end of the main stent lumen.Multiple lumens 140 are located at the distal portion of member 42 andextend along the entire length of the inner member 42. Lumens 140 may bein communication with one or more flush ports at the handle portion ofthe delivery system whereby saline may be flushed through lumens 140 ata pressure greater than that of the surrounding blood flow to preventblood flow through the device lumens. Lumens 140 may also be used todeliver radiopaque contrast dye used during fluoroscopically visualizedplacement of the device. Lumens 140 and the exit ports 186, describedbelow, allow for visualization of the dye flowing through the implant atvarious stages of deployment in order to verify that placement of thestent yields a satisfactory flow pattern and therapeutic result.

In other embodiments, such as that illustrated in FIGS. 10A, 10B and10C, attachment string lumens 140 may extend along only a portion of thelength of inner member 40, e.g., only a few millimeters distally toproximally. This embodiment is particularly suitable in the case whereonly one attachment string is employed with multiple stent connectionpoints. Here, the single string element exits one of the distal lumens,is passed through the stent connection point, is passed distally toproximally through another of the lumens, exits proximally from thatlumen and is passed through another of the lumens distally to proximallyand passed through another stent connection point. The interlacingpattern continues until all stent connection points are laced with thesingular string which passes through the multiple circumferentiallumens. This configuration of attachment string lumens which extend onlya portion of the length of the inner member, may also be employed withthe intermediate member 40 and with the side branch catheters 94 a, 94b, 94 c. With respect to an intermediate member employing such a stringlumen configuration, the proximal portion of intermediate member 40would be a single lumen containing the inner member 42 and the shortercircumferential lumens would contain the side branch catheters as wellas the attachment wires for the proximal end of the main stent lumen. Aswill be seen from this embodiment and those discussed below, anycombination of lacing patterns may be used to attach an individual stentend to the respective catheter to which it is attached.

Referring again to the embodiment FIG. 6A, the number of distalattachment strings lumens 140 is double the number of attachment strings132 where one pair of adjacent attachment strings lumens 140 a, 140 b isprovided for each distal attachment string 132. As such, where device120 is fully loaded within the deployment system, the first portion of adistal attachment string 132 resides within lumen 140 a and a second orreturn portion of the distal attachment string resides within lumen 140b.

In addition to attachment string lumens 140 are one or more steeringpull-wire lumens 142, the function of which is as described above withrespect to FIG. 4. Typically, one or two pairs of diametrically opposed(180° apart) steering pull-wires are employed to provide opposingorthogonal deflections of the distal end of the delivery system. Thegreater the number of steering pull-wire pairs employed, the greater thedirections of steering in articulating the delivery system.

In addition to central lumen 138 through which inner member 42 istranslated, intermediate member 40 includes a plurality of proximalattachment string lumen pairs 146 a, 146 b where lumen 146 a is shownsituated radially outward from lumen 146 b. The attachment stringsattached to or threaded through the proximal crowns (not shown) of mainlumen 122 of device 120 utilize lumens 146. The number of proximalattachment string lumens 146 is double the number of proximal attachmentstrings where one pair of attachment string lumens 146 a, 146 b isprovided for each proximal attachment string, i.e., where device 120 isfully loaded within the delivery and deployment system, the fixed-endportion of a proximal attachment string resides within lumen 146 a andthe distal or return portion of the proximal attachment string resideswithin lumen 146 b.

In addition to attachment string lumens 146, intermediate member 40 alsoprovides a plurality of lumens 148, also circumferentially disposedabout central lumen 138 and preferably interposed between pairs ofproximal attachment lumens 146, where one or more of the lumens 148 maybe employed to translate and deliver a side branch catheter 150 (shownin FIG. 6A without detail). Side branch catheter 150 provides a centralside branch guide wire lumen 152 for delivering and translating a sidebranch guide wire 154. Additional lumens 148 extending from a handleflush port (not shown) may be provided for evacuating air from thedelivery system 30. The additional lumens 148 may also allow for therehydration of tissue graft coverings or other coverings which need tobe prepared with solutions and potential therapeutic agents such aspharmacologics, stem cells, or other agents. This allows the stent graftor other device to be constrained in the delivery catheter in a drieddehydrated state subsequently packaged, sterilized, and rehydrated bythe flushing and preparing the catheter at the time of use. Any unusedlumens 148 provide enhanced flexibility of the intermediate member,particularly where the distal end of the device is deflectable atmultiple articulation points.

FIGS. 7A, 7B and 7C illustrate various possible embodiments of sidebranch catheters suitable for use with the delivery system of thepresent invention. Side branch catheter 160 of FIG. 7A provides acentral guide wire lumen 162 and plurality of attachment string lumens164 arranged circumferentially about central lumen 162. Lumens 164 areutilized or occupied by the attachment strings (not shown) which arelooped or threaded through the distal crowns 128 of side branch lumen124 of device 120 (see FIG. 5A). The number of side branch attachmentstring lumens 164 is double the number of side branch attachment stringswhere one pair of attachment string lumens 146 a, 146 b is provided foreach side branch attachment string, i.e., where device 120 is fullyloaded within the implantation system, the proximal portion of a sidebranch attachment string resides within lumen 164 a and the distal orreturn portion of the side branch attachment string resides within lumen164 b.

Side branch catheter 170 of FIG. 7B provides an outer member 172 havinga central lumen 174 and an inner member 176 positioned concentricallytherein. Inner member 176 also has a central lumen 178 for translatingand delivering a side branch guide wire (not shown). Outer member 172further provides a plurality of side branch attachment string lumens 180where there is a one-to-one correspondence between the number of sidebranch attachment string lumens 180 and the number of side branchattachment strings (not shown). In this embodiment, the proximal portionof side branch attachment strings reside within the space between theinternal diameter of outer member 172 and the external diameter of innermember 176 and after being looped through the distal attachment eyelets,crowns or cells, the distal or return portion of the strings passthrough lumens 180 of outer member 172.

In another embodiment of side branch catheter 200, shown in FIG. 7C theside branch catheter can be composed of two concentric single lumens.One single lumen tubing 202 defining an internal diameter and anothersingle lumen tubing 203 defining an outer diameter provides for the sidebranch attachment strings to be contained within the space 201 betweenthe internal diameter of the outer tubing 202 and the outer diameter ofthe inner tubing 203. The internal diameter of the inner tubing is usedto translate a guidewire (not shown) through side branch guidewire lumen204 which is isolated from the attachment strings as shown in FIG. 7C.This lumen configuration may also be employed with the intermediate andinner members.

Referring to FIG. 6B, there is shown a cross-sectional view taken alonglines B-B of FIG. 5C, specifically through a proximal end of distal tip46 where inner member 42 terminates. Distal tip 46 provides the distalportion of guide wire lumen 44 as well as the distal lumen portions 182of distal attachment string lumens 140 of inner member 42 where theplurality of distal lumen portions 182 are axially aligned and have aone-to-one correspondence with inner member attachment string lumens140. As such, the same pairing of adjacent attachment string lumens 182a, 182 b is provided for each distal attachment string 132, i.e., wherethe fixed-end portion of a distal attachment string 132 resides withinlumen portion 182 a and the releasable or return portion of the distalattachment string resides within lumen portion 182 b. As is bestillustrated in FIG. 6C, after passing within lumen portions 182 a, theattachment strings 132 are passed radially out of distal tip 46 throughdesignated proximal side ports 184. The attachment strings are thenlooped or threaded around eyelets 130 or crowns or apices 126 or throughthe very distal cells of main lumen 122, and threaded back through thedesignated side port 184 of distal tip 46 whereby they re-enterrespective lumen portions 182 and respective attachment string lumens140. As such, for every pair of attachment string lumens, there are halfas many side ports 184, i.e., there is a one-to-one correspondencebetween the number of attachment strings 132 and the number of distaltip side ports 184. Distal tip 46 also provides for distal side ports186 to facilitate the loading of strings during assembly of the implantto the deliver system.

The catheters and/or guidewires employed with the systems of the presentinvention may include intravascular ultrasound (IVUS) imagingcapabilities where one or more miniaturized transducers are mounted onthe tip of a catheter or guidewire to provide electronic signals to anexternal imaging system. Such a transducer array may rotate to producean image of the lumen of the artery showing the precise location of thetake offs for the connected branch vessels that will receive theconnected branch stents or other cavities into which the catheter isinserted, the tissue of the vessel, and/or the tissue surrounding thevessel. In addition to facilitating visualization during stent deliveryand deployment, such systems enhance the effectiveness of diagnosis andtreatment by providing important diagnostic (i.e., pre-stenting)information, e.g., the location and size of an aneurysm, that is notavailable from conventional x-ray angiography. Intravascular ultrasound(IVUS) imaging catheters are commonly used as a preliminary step in theprocedure of selecting the appropriately sized stent graft beforeplacing a non-branched stent for several reasons which include to ensurethat coverage of a side branch vessel is not mistakenly done. Combiningthe imaging ability into the tip of the stent delivery catheter has theadvantages of saving time by avoiding a catheter exchange. A secondtechnique which is commonly done to avoid the exchanging of the stentdelivery catheter and the IVUS catheter through the access site is togain another access point to introduce the separate IVUS catheter. Byintegrating the IVUS transducers on the tip of the stent deliverycatheter, one eliminates the need for a second vascular access woundshould the imaging catheter have been delivered through a bilateralgroin access location. Also, when placing a stent inside another stent,an IVUS catheter is used to ensure that the second stent will bedeployed within the lumen of the first stent in an overlapping fashionto extend the coverage length of the treated region. In those cases, afirst stent has been placed and the downstream portion is free floatingwithin a large aneurysm sac and, as such, care must be taken to ensurethat the second stent to be placed within the first stent is not outsidethe lumen of the first stent. To do otherwise, may result inunintentionally occluding the vessel requiring the procedure to beconverted to a surgery to remove the misplaced second stent.

Methods of Device Implantation

The implantation procedure for the subject devices will now be describedwith respect to FIGS. 8A-8H and in the context of an aortic archapplication in which a stent-graft 2 of the present invention, such asthat illustrated in FIG. 1A, having a main body lumen 4 and three sidebranch lumens 6 a, 6 b and 6 c, is percutaneously implanted within theaortic arch 5, where, upon implantation, main body lumen 4 will residewithin the aortic arch 5 and the three side branch lumens 6 a, 6 b and 6c will reside in the innominate artery 7 a, the left common carotidartery 7 b and the left subclavian artery 7 c, respectively, asillustrated in FIG. 8H.

By means of a Seldinger technique via the left femoral artery 8, orabdominal aortatomy, a main or aortic guide wire 48 is advanced throughthe vasculature to the aortic arch 5 up to or until distal tip 48 a iscaused to cross the aortic valve 10, as illustrated in FIG. 8A. Catheterportion 32 of the implantation system 30 of the present invention,provided with stent-graft 2 operatively loaded therein, is thenpercutaneously introduced into the patient's body over guide wire 48.

It is noted that stent-grafts or stents otherwise covered with amaterial, e.g., an ECM, may require reconstitution or hydration of thegraft or covering prior to commencing the implantation procedure. Thismay be accomplished by flushing the guide wire lumen of delivery systemcatheter with saline prior to inserting the catheter into the body.Alternatively this could be done by rinsing in open air prior tosheathing.

While stent graft 2 is in a loaded, undeployed state within catheterportion 32, the delivery system's handle is in the retracted position,i.e., proximal handle portion 34 a and distal handle portion 34 b areengaged with each other. With the handle in the retracted position(shown in FIGS. 8B and 8D), inner member 42 is held in a distallyadvanced position and intermediate member 40 is held in a proximallyretracted position. This relative axial relationship between theintermediate and inner members, maintains stent graft 2, or at least itsmain lumen 4, in a stretched or tensioned condition. This is so as thedistal crowns of main lumen 4 are attached to the distal end of innermember 42, which in turn is fixed to proximal handle portion 34 a, andthe proximal crowns of main lumen 4 are attached to the distal end ofintermediate member 40, which in turn is fixed to the distal handleportion 36 b.

Catheter portion 32 is then steered as necessary by means ofmanipulating lever 56, thereby deflecting the distal tip of catheter 32,as described above with respect to FIG. 4, and advanced into thedescending aorta and then into aortic arch 5. It is important thatcatheter portion be properly rotationally positioned so that side branchlumens 6 a, 6 b and 6 c of stent graft 2 are substantially aligned witharteries 7 a, 7 b and 7 c, respectively, into which they are to bedelivered. To this end catheter 32 is torquable and fluoroscopicguidance may be employed to further facilitate delivery of catheterportion 32. In particular, fluoroscopic markers (not shown) on thecrowns of the stent graft lumens may be tracked and accuratelypositioned for optimal placement within the respective arteries. Thestent itself may be radiopaque. The tip of the catheter will beradiopaque as well. A steerable guidewire may be used to direct the maincatheter 32 and the side branch catheters as the stretched main stentbody and side branch stent bodies are steered by deflectable tippedguidewires placed into the target implant site.

Throughout the delivery and deployment procedure, the various lumens ofcatheter portion 32 may be continuously flushed with a fluid, e.g.,saline or contrast agent, in a retrograde direction (relative to theblood flow) at a pressure that is greater than or substantially equal tothe pressure of the arterial blood. This prevents possible leakage ofblood from the system as well as prevents any interference with thefunctioning of the delivery process, particularly keeping the stentstrings lumens free and clear of blood, thereby eliminating clottingwithin the lumens. Additionally, because each lumenal end of the stentgraft (i.e., the proximal and distal ends of main lumen 4 as well as thedistal ends of the side branch lumens) is individually controlled(however, some or all may be collectively controlled) by the deliveryand deployment system 30 of the present invention, the interconnectedcells of the stent may be selectively elongated in an axially direction,permitting the continual flow of blood around the device duringdeployment within the anatomy. This axial elongation feature alsopermits the implantation of larger diameter side branch stents within avessel having a smaller diameter.

Once the distal end of catheter portion 32 is operatively positionedwithin the aortic arch 5, outer sheath 38 is retracted by manuallypulling on fitting 50 (see FIG. 3A) to expose the proximal end of nosecone 46 of inner member 42 and to partially deploy the distal portion ofthe main or aortic lumen 4 of stent graft 2 within the ascending aorta,as shown in FIG. 8C. With partial deployment of stent graft 2, i.e.,main aortic lumen 4 is maintained in a stretched or tensioned state,arterial blood flow exiting from aortic valve 10 flows through andaround main lumen 4. It is important to note that with main lumen 4 inthis partially deployed state, stent graft 2 can be easily repositionedwithin the vasculature as it is not yet engaged with the vessel wallsand, thus, is not subject to the frictional resistance that contact withthe walls would cause, not to mention the avoidance of the resultingendothelial damage and/or plaque embolization which is likely to occur.

While the various side branch lumens 6 a, 6 b and 6 c of stent graft 4may be deployed serially (one at a time) in any order or parallely(simultaneously) together, it may be easiest to deploy the side branchstent lumens one at a time in order from the most distally positionedstent lumen (6 a) to the most proximally positioned stent lumen (6 a).This deployment order eliminates unnecessary or repetitious translationof outer sheath 38 over the stent graft, i.e., only gradual,unidirectional (proximal) translation is necessary. This is advantageousin that abrasions to the graft material are minimized, which isparticularly important when coated with a material, e.g., extra cellularmatrix, or a drug. This deployment order further reduces the necessarydeployment steps and, thus, the total time necessary for theimplantation procedure.

To deploy a side branch stent lumen, such as stent lumen 6 a, a sidebranch guide wire 154 is inserted into (or may be preloaded within) sidebranch port 110 of the respective control hub in its full distallyadvanced position and into a lumen 152 of side branch catheter 150positioned within lumen 148 of intermediate member 40 (see FIG. 6A). Atthe same time, outer sheath 38 is incrementally and gradually retractedproximally to allow the distal end of guide wire 154 to be translatedthrough side branch catheter 150, out its distal end and into innominateartery 7 a, as shown in FIG. 8C. The respective control hub 74 is thendistally translated along intermediate member 40 and may be fullyengaged with the associated catheter hub 84, thereby exerting maximumtension being applied to the side branch stent cells by the attachedattachment strings and partially deploying side branch stent 6 a asshown in 8D. Note that the main body stent cells are being heldstretched distal to proximal through the relative positions of the innermember and intermediate member as controlled by the handle in the closeconfiguration while the side branch stent is likewise maintained in astretched position by the distally advanced side branch catheter. Thisprocedure is repeated as necessary for the remaining number of sidebranch stents, in this case, side branch stents 6 b and 6 c which aredelivered into the left common carotid artery 7 b and the leftsubclavian artery 7 c, respectively, as illustrated in FIG. 8D. Notethat at this partially deployed state the blood flow is around thedevice as well as through the implant depending on how tight and overwhat extension length the attachment strings are pulled to the innermember exit ports 184. It may be desirable to have just flow around thedevice and not through the lumen of the device and that can beaccomplished by cinching down on the attachment strings on the distalend of main lumen to allow the most minimal length of attachment therebybringing the main lumen of stentgraft to be held closed against distaltip 46 or inner member 42. It is important to note that the distancebetween the distal main stent end and its connection to the inner memberis controllable by the length of distal attachment strings which arecontrolled by the string clamp 70 b by adjusting and selecting thelocation of where the clamp locks onto the distal attachment strings.This adjustment can be made in situ while the stent is being delivered.Likewise the distance between the proximal main stent end and itsconnection to the intermediate member is controllable by the length ofproximal attachment strings which are controlled by the string clamp 72b by adjusting and selecting the location of where the clamp locks ontothe proximal attachment strings. This adjustment can be made in situwhile the stent is being delivered.

After placement within the branch arteries of all of the side branchstents in their partially deployed states, the stent graft is ready forfull deployment. This is accomplished by moving the system handle to theextended position, i.e., proximal handle portion 34 a and distal handleportion 34 b are axially separated from each other, as illustrated inFIG. 8E. This action causes inner member 42 to translate proximallyrelative to the fixed intermediate member 40 and in turn relaxes thetension applied to the cells of main lumen 4, thereby bringing the lumenends closer together. As such, the stent foreshortens and there is acorresponding increase in the diameter of main lumen 4, thereby securingmain lumen 4 against the walls of the aorta.

The side branch catheters are likewise translated proximally by movingthe respective control hub 74, 76, 78 a distance further from itscorresponding catheter hub 84, 86, 88 thereby relaxing the tensionapplied to the cells of the side branch stent. As such there is acorresponding increase in the diameter of side branch lumens 6 a, 6 b, 6c as the lumenal ends foreshorten. It is important to note that thedistance between the stent ends and the catheter end is controllable byadjusting the length of the strings traversing between the fixed-endknob 70 a, 72 a, 74 a, 76 a, 78 a and the releasable end clamp 70 b, 72b, 74 b, 76 b, 78 b.

Once the stent cells have been released of their tension by thetranslation of the catheter handle and side branch catheters, and as thestent opens to a diameter which is expanded against the surroundingartery wall, the entire blood flow enters through the distal end of thedevice and exits all of its other lumens. Preferably, blood flow issealed from around the outside of the stentgraft once the stent has beenfully deployed.

While the stent itself may be fully deployed as shown in FIG. 8E, it isstill attached by attachment string sets to each of the distal ends ofinner member 42, intermediate member 40 and each side branch catheter150 a, 150 b, 150 c. The lumenal ends of the stent graft can now bedetached from their respective catheters. The stent graft's lumenal endsmay be released serially (one at a time) in any order or parallely(simultaneously) together. As shown in FIG. 8F, the lumenal ends of theside branch lumens 6 b and 6 c have been released, with the respectiveattachment strings 190, side branch catheters 150 a, 150 b, 150 c andside branch guide wires 154 having been retracted. For each side branchlumenal end, such as illustrated for side branch lumen 6 a, catheterdetachment is accomplished by actuating the designated control clamp 74b, 76 b and 78 b on its respective catheter hub 74, 76, 78 to releasethe free ends of strings 190 from the screw clamp of catheter hub and,at the same time, by removing control knob 74 a, 76 a, 78 a from thehandle and pulling strings 190 to the extent that the free ends unloopor detach from the respective stent's crowns 128 of FIG. 8F. The strings190 need only be pulled until their free ends release the crowns but maybe withdrawn within the distal end of catheter portion 32.

As illustrated in FIG. 8G, a similar procedure is performed with respectto deployment of the distal and proximal ends of main lumen 4, whereeither end may be deployed first or both ends may be deployedsimultaneously The designated control clamp 70 b, 72 b is actuated torelease the free ends of strings 192 and, at the same time, controlknobs 70 a, 72 a is removed from the handle thereby pulling strings 192to the extent that the free ends unloop or detach from the respectivestent's crowns 126. Strings 192 need only be pulled until their freeends release the crowns but may be withdrawn within the distal end ofcatheter portion 32. The entirety of catheter portion 32 may then beremoved from the vasculature with stent graft 2 in a fully deployedstate within the aortic arch 5, as shown in FIG. 8H.

Referring now to FIG. 11, the partial deployment step of the abovedescribed procedure is illustrated with respect to the delivery anddeployment of the implant 210 of FIG. 1E. Specifically, catheter portion38 of the delivery system is positioned within the aorta with the distalportion of main stent lumen 122 partially deployed within the aorticroot and ascending aorta 240, and side branch lumens 214 a and 214 bpartially deployed within the right and left coronary ostia 220 and 222,respectively. A main guidewire 218 extends from catheter 38 and crossesthe former location of the natural aortic valve 224, while side branchguidewires 226 and 228 extend within the coronary ostia 220, 222 fromside branch catheters 230 and 232, respectively. Upon release of theattachment strings for the main lumen of the implant, prosthetic aorticvalve 216 will reside within the natural annulus 224. The side branchlumens 214 a, 214 b may be deployed simultaneously with each other andwith main lumen 212, or serially in any order.

In any surgical or endovascular procedure, such as the one justdescribed, the fewer incisions made within the patient, the better. Ofcourse, this often requires highly specialized instrumentation and toolsused by a highly skilled surgeon or physician. In consideration of this,the above-described single-incision device implantation procedure may bemodified to include the creation and use of one or more secondaryincisions to facilitate the initial delivery of the catheter portion 38of the delivery system 32 at the implantation site and to further ensureproper orientation of the stent graft upon its deployment at the site.

The two-incision (or multiple-incision) procedure of the presentinvention involves a primary incision, e.g., a cut-down in the femoralartery as described above, through which the above-described deliveryand deployment system is introduced into a first vessel within the body,e.g., into the aortic arch, and a second incision (or more) at alocation(s) that provides access to at least one vessel which intersectsthe first vessel, e.g., one of the side branches of the aortic arch.This procedure is now described with reference to FIGS. 12A-12F and inthe context of implanting the stent graft 2 of the present invention inthe aortic arch by use of a primary incision made in the left femoralartery 8 to access the aortic arch 5 and a single secondary incisionmade in the brachialcephalic or radial artery 15 to access one or morearteries of the aortic tree.

First and second access incisions are made—in the left femoral artery 8and the left brachycephalic artery 15, respectively. By means of aSeldinger technique, a secondary or “tether” guide wire 300 is advancedthrough the left brachycephalic artery 15 into the innominate artery 7.Guide wire 300 is then further advanced into the aortic arch 5, thedescending aorta 11, the abdominal aorta 13 and the left femoral artery8 where it exits the body through the femoral incision, as illustratedin FIG. 12A. A secondary or “tether” catheter 302 is then tracked overthe femoral end 300 a of guide wire 300 and along the length of theguide wire until catheter 302 is advanced out of the brachial incision,as illustrated in FIG. 12B. Any suitable off-the-shelf system forcardiovascular applications may be employed for use as the secondary ortether guide wire and catheter. A dual lumen rapid-exchange (RX)catheter, such as the one illustrated, having a second lumen positionedat the proximal end of catheter 302. An advantage of an RX catheter isthat it only requires the string(s) (or a guidewire) to be pushed arelatively short distance (requiring little “pushability”) before itexits the lumen rather than a greater distance in which the string wouldbe difficult to push due to its limp nature. Alternatively, the very endof catheter 302 may be provided with a thru-hole or a cross-hole in thecatheter wall, as illustrated in FIG. 12C′.

The above descried implantation system 30 is then provided withstent-graft 2 operatively loaded therein. For this procedure, asillustrated in FIG. 12C, side branch attachment strings 190, or at leastone string thereof, for deploying the most distally located side branchstent lumen 6 a (i.e., the one intended for implantation into theinnominate artery 7 a) and attached thereto (to one or more stentcrowns) are extended from side branch catheter 150 a of primary or stentdelivery system catheter 38 and then threaded through a side branchtether tubing 35. The strings are then knotted 37 a to prevent proximalwithdrawal back into catheter 150 a and tubing 35. The remaining distallength of strings 190 are then threaded through the exchange lumen 304of tether catheter 302. The ends of the strings are then knotted asecond time 37 b to prevent proximal withdrawal of the strings fromexchange lumen 304. With the secondary catheter embodiment of FIG. 12C′,the strings are threaded into the main lumen 302 and out the side hole305. The distal string ends are then knotted 37 b.

Secondary catheter 302, with side branch catheter 150 a in tow as wellas the entirety of stent catheter 38 including primary or main guidewire 48, is then advanced back through the femoral incision oversecondary guide wire 300 until catheter 302 is fully withdrawn from thebrachial incision, as illustrated in FIG. 12D, and until the distal endof side branch catheter 150 a is also extended from the brachialincision. Tether guide wire 300 can now be removed from the body. Atthis point, strings 190 are cut at a location 307 between the distal endof side branch catheter 150 a and the opposing end of secondary catheter302 to release the tether catheter 302 from the stent deployment system.

By the tension applied to strings 190 and the translation thereof, sidebranch 6 a of stent graft 4 has been drawn into the innominate artery 7a, as illustrated in FIG. 12E, in a partially deployed state (i.e.,exposed but stretched). Concurrently, stent guide wire 48 is advancedover the aortic arch 5 and across the aortic valve 10, thereby advancingnose cone 46 and thus the distal end of the partially deployed (i.e.,exposed but stretched or tensioned) main stent lumen 4 into theascending aorta. Meanwhile, stent catheter 38 has been tracked overstent guide wire 48 into the aortic arch 5. Continued forwardadvancement of stent catheter 38 is blocked by the partially deployedside branch lumen 6 a. As discussed above, with main lumen 4 maintainedin a stretched or tensioned state (as well as side branch lumen 6 a),various advantages are provided: arterial blood flow exiting from aorticvalve 10 is allowed to flow to the brain and body; repositioning of thestent graft 2 is possible, and the likelihood of endothelial damageand/or plaque embolization from the aortic wall is greatly minimized.

For stents and stent grafts having two or more side branch lumens 6 a, 6b, 6 c, as in FIG. 12F, the procedure described above and illustrated inFIGS. 12A-12E with respect to the implantation of a stent having asingle side branch lumen is simultaneously performed, with separatedesignated tether guide wires and catheters 150 a, 150 b, 150 c. Asillustrated in FIG. 12F, with at least the distal end of the main stentlumen 4 accurately positioned and partially deployed within theascending aorta, the respective side branch lumens 6 a, 6 b, 6 c aredeployed within the innominate artery 7 a, left common carotid artery 7b and the left subclavian artery 7 c, respectively. Alternatively, oneor more of the side branch lumens may be partially deployed as describedwith respect to FIGS. 12A-12F, and the remaining side branch lumens, ifany, may be deployed in the manner described above with respect to FIGS.8C and 8D. Finally, with all side branch lumens 6 a, 6 b, 6 c partiallydeployed within their respective arteries, the procedural stepsdescribed with respect to FIGS. 8E-8H may be performed to fully deploythe all lumens of the stent graft and remove the delivery system fromthe body.

While the implants of the present invention have been described as beingdeployable by elongated members, i.e., strings, it is understood thatthe subject implants may be configured such that their lumenal ends areconfigured for deployment by an expandable member or members. Forexample, each of the ends of the implant (i.e., of the main lumen and ofthe side branch lumen(s)), in a loaded, undeployed state, may be coupledto one or more of the nested catheters by placement about an expandableballoon affixed to the catheter(s). The balloons, in either a partiallyor fully expanded state, provide a sufficiently snug fit with theimplant ends such that the lumens of the implant may be selectivelystretched or tensioned along their lengths when manipulating thecatheter components.

The preceding merely illustrates the principles of the invention. Itwill be appreciated that those skilled in the art will be able to devisevarious arrangements which, although not explicitly described or shownherein, embody the principles of the invention and are included withinits spirit and scope. Furthermore, all examples and conditional languagerecited herein are principally intended to aid the reader inunderstanding the principles of the invention and the conceptscontributed by the inventors to furthering the art, and are to beconstrued as being without limitation to such specifically recitedexamples and conditions. Moreover, all statements herein recitingprinciples, aspects, and embodiments of the invention as well asspecific examples thereof, are intended to encompass both structural andfunctional equivalents thereof. Additionally, it is intended that suchequivalents include both currently known equivalents and equivalentsdeveloped in the future, i.e., any elements developed that perform thesame function, regardless of structure. The scope of the presentinvention, therefore, is not intended to be limited to the exemplaryembodiments shown and described herein. Rather, the scope and spirit ofpresent invention is embodied by the appended claims.

1. A method of placing a stent at a target site within vasculaturecomprising a main vessel and at least one side branch vessel in fluidcommunication with the main vessel, the stent comprising a main lumenand a at least one side branch lumen, the method comprising: creating anincision within the vasculature; advancing a catheter through thevasculature from the incision to a target site; deploying a stent fromthe catheter at the target site wherein the stent is in a reduceddimension inside the catheter and expands to an expanded dimension inthe vessel, and further wherein the stent comprises a main lumen and atleast one side branch lumen; and adjusting the side branch lumenrelative to the main lumen to position the side branch lumen in a sidebranch vessel.
 2. The method of claim 1 further comprising allowingextracellular matrix on the stent to integrate the stent into the targetsite.
 3. The method of claim 1 wherein the stent is deployed withoutcompletely disrupting blood flow in the main vessel.
 4. The method ofclaim 1 further comprising viewing at least one of the acts of themethod using an imaging system.
 5. The method of claim 4 wherein theimaging system comprises use of radiographic dye or fluoroscopy.
 6. Themethod of claim 4 further comprising injecting a visualization materialinto the vessel.
 7. The method of claim 4 wherein the imaging systemcomprises intravascular ultrasound.
 8. The method of claim 7 furthercomprising employing a guidewire to implant the stent wherein the distaltip of the guidewire comprises at least one intravascular ultrasonictransducer.
 9. The method of claim 1 wherein only a single incision ismade.
 10. A method of placing a stent at a target site withinvasculature comprising a main vessel and at least one side branch vesselin fluid communication with the main vessel, the stent comprising a mainlumen and a at least one side branch lumen, the method comprising:creating a first incision at a first location within the vasculatureleading to the target site; creating a second incision at a secondlocation within the vasculature leading to the target site; positioningthe main lumen of the stent within the main vessel using at least oneline extending from the first incision; and positioning a side branchlumen within a side branch vessel using at least one line extending thesecond incision; wherein selective tensioning of the lines partiallydeploys the stent at the target site; and wherein releasing the linesfully deploys the stent at the target site.
 11. The method of claim 10,further comprising placing a extracellular matrix around at least aportion of the stent prior to placing the stent in a vessel.
 12. Themethod of claim 11, further comprising allowing the extracellular matrixto integrate the stent into the main vessel wall at the target site. 13.The method of claim 10, further comprising; placing the stent in acatheter comprising a lumen having proximal and distal ends; insertingthe distal end of the catheter into the first incision; and navigatingthe distal end of the catheter to the target site.
 14. The method ofclaim 13, further comprising deploying the stent from the catheter. 15.The method of claim 13, further comprising imaging the vasculature usingan imaging system.
 16. The method of claim 15, further comprisingadjusting the position of the stent at the target site using the imagingsystem and the first and second lines.
 17. The method of claim 10,wherein the first incision is made in a femoral artery and the second ismade at a location in the vasculature to provide access to at least oneof the innominate artery, the left carotid artery and the leftsubclavian artery.
 18. The method of claim 17, wherein the secondincision is made in the brachiocephalic artery.
 19. The method of claim10, wherein the first incision is made in the brachiocephalic artery andthe second incision is made in an iliac artery
 20. The method of claim10, wherein the stent is positioned and deployed without completelydisrupting blood flow in the vasculature.
 21. A method of treating anaortic aneurysm of a human patient, comprising: creating a firstincision in a first location of a vessel leading to an aneurysm in apatient's aortic artery; creating a second incision in a second locationof a vessel leading to the aneurysm; and moving a stent to a target siteat the aneurysm using a first line connected to the stent and exitingthe first incision and using a second line connected to the stent andexiting the second incision.
 22. The method of claim 21, furthercomprising: imaging the interior of a vessel while moving the stent tothe target site.
 23. The method of claim 21, further comprising:tensioning the first and second lines and thereby reducing an outerdimension of the stent.
 24. The method of claim 21, further comprising:placing a extracellular matrix around at least a portion of the stentprior to placing the stent in a vessel.
 25. The method of claim 24,further comprising: allowing the extracellular matrix to integrate thestent into the main vessel wall at the target site.